Born powerless, Arabel is abandoned in twilight by her lumin parents. Raised by greys, she is treated like an outsider for most of her life, yet when her enclave is raided by lumin soldiers, Arabel vows to rescue her people at any cost.
In spire city Coronus, Supreme Solar Roland discovers a dangerous firearm that violates the Great Edict – All machinery and weapons must be powered by lumins. Roland casts a suspicious eye upon the twilight dwelling greys, and ponders the relevance of their existence.
Two nations that once lived in harmony have become divided by prejudice and fear. But conflict will not restore their fractured bonds. Only the return of sun givers can set Tandor's people on a path to reforging their broken ties. Only a sun giver can save them from destroying one another. But a sun giver hasn't been discovered in generations…